The embodiments relate to an explosion-proof electronic device and a manufacturing method thereof.
In environments where combustible gas is generated, such as in petroleum refining plants, crude stations, and paint factories, or in environments where dust is generated, such as in coal mines, explosion-proof electronic devices are used.
An explosion-proof electronic device has a configuration, for example, in which plural printed circuit boards with components mounted thereon are arranged and a resin filler is provided so as to cover the printed circuit boards and the components thereon. In such a configuration, combustible gas or dust can be prevented from coming into contact with the printed circuit boards and the components thereon.
The plural printed circuit boards are connected in the following manner, for example. A male connector is attached to one surface of one of the plural printed circuit boards while a female connector is attached to one surface of another printed circuit board, and the male and female connectors are fit to each other.
When the filler is put into space between the connected printed circuit boards, the filler can penetrate into the connectors through a gap at the interface between the male and female connectors and in some cases cause electrical contact failure at the connection of the connectors. From this perspective, to ensure the connection in the explosion-proof electronic devices, the filler is inhibited from penetrating into the connectors.
To solve this problem, Japanese Patent Laid-open Publication No. 2010-154708 (PTL 1) discloses the following technique. A connector packing is provided like a wall so as to surround the outer circumference of each connector provided on a printed circuit board. The connector packing is pressed by a member supporting plate placed facing the printed circuit board, to seal the connector. The space between the printed circuit board and member support plate is then filled with a filler. The filler can be thus prevented from penetrating into the connector.